Referring to FIG. 1, in the field of communications technologies nowadays, during handover from a non-worldwide interoperability for microwave access broadband wireless access technology (Worldwide Interoperability for Microwave Access, WiMAX) network to a WiMAX network, a terminal uses a single-radio-frequency handover manner. The terminal first performs ranging, base station capability negotiation, pre-authentication and interaction between attached networks with a virtual WiMAX base station through a tunnel in the current non-WiMAX network, thereby entering the WiMAX network. Next, an initiate handover manner or idle mode handover manner is adopted, so the terminal is handed over from the virtual base station to a target base station or enters an idle mode of the WiMAX network. After the terminal is handed over to the radio frequency of the WIMAX network, WiMAX network re-entry is performed from the target base station on an air interface of the terminal, so as to complete a network handover procedure.
In the initiate handover manner, a terminal initiatively sends a handover request message to a virtual base station, where the handover request message includes information of one or more candidate target base stations discovered by the terminal. After receiving the handover request message, the virtual base station interacts with each candidate target base station, so as to enable each candidate target base station to perform handover preparation for the terminal. After receiving a handover response message from the virtual base station, the terminal sends a handover indication message to the virtual base station, so as to specify a finally determined handover target base station. After the terminal is handed over from a non-WiMAX radio frequency to a WiMAX radio frequency on an air interface, the terminal and the determined target base station perform the operations such as ranging to complete WiMAX network re-entry, so as to finally complete a handover procedure. After performing the radio frequency handover in such a handover manner, the terminal and the target base station perform a step of network re-entry, which usually includes ranging and capability negotiation, and the complete authentication is no longer required.
In the idle mode handover manner, a terminal sends a request message to a virtual base station, and requests to enter an idle mode. The virtual base station returns a response message for confirming to enter the idle mode, instructs a network to perform proper processing, records the terminal as being in the idle mode, and the terminal is temporarily not handed over to a target base station. In the idle mode, the network releases resources relevant to the terminal as much as possible, and only reserves indispensable information, such as authentication information, and information about an attached base station. After the terminal is handed over, on an air interface, to a WiMAX radio frequency, the terminal may indicate exit of the idle mode in a ranging request during network re-entry with the target base station selected by the terminal. Subsequently, the network performs the processing of exiting the idle mode on the terminal, and the complete authentication is no longer required. In this procedure, the terminal does not perform a base station handover action, but the terminal enters the idle mode from the virtual base station, and subsequently exits the idle mode from the target base station, so as to actually achieve the objective of handover from the virtual base station to the target base station.
During the practice and research of the conventional art above, inventors of the present invention find that:
When a terminal is handed over from a non-WiMAX network to WiMAX, initiate handover or idle mode handover is adopted, but which method is adopted to perform handover is deployed on a virtual base station and decided by the virtual base station. The terminal attempts to perform handover in one manner first, and if the handover is rejected by the virtual base station, the handover is performed in another manner. In this way, the handover time is delayed and the efficiency is not high.